Methanol → 2-Difluoromethyl-5-hydroxy-pyran-4-one

To an ice-salt cooled, clear solution of 5-benzyloxy-2-difluoromethyl-pyran-4-one (252 mg, 1 mmol) in CH2Cl2 (4 mL) was added dropwise a solution of 1.0 M BBr3 in CH2Cl2 (1 mL, 1 mmol) diluted with CH2Cl2 (1 mL). After 10 min, TLC analysis of the reaction mixture using a mixture of CH2Cl2 and MeOH (20/1, v/v) as eluant indicated consumption of the starting material. The reaction mixture was quenched with MeOH (5 mL), and evaporated to dryness. The residual oil was taken up in ethyl acetate (30 mL), and the organic layer was washed with brine (2×10 mL), dried over sodium sulfate. The mixture was filtered, and the filtrate was concentrated in vacuo to give a solid. The solid was triturated with ether, and was then collected by suction filtration. The title compound was obtained as an off-white solid (80 mg, 50% yield). The purity (peak area percent is 97.3%) of this material was analysed by HPLC Method 1 as described above. 1H NMR (400 MHz, DMSO-D6) δ (ppm): 9.59 (s, 1H), 8.22 (s, 1H), 6.93 (t, J=52.8 Hz, 1H, CF2H), 6.76 (s, 1H).

1. customconsumption of the starting material
2. customThe reaction mixture was quenched with MeOH (5 mL)
3. customevaporated to dryness
4. washthe organic layer was washed with brine (2×10 mL)
5. dry with materialdried over sodium sulfate
6. filtrationThe mixture was filtered
7. concentrationthe filtrate was concentrated in vacuo
8. customto give a solid
9. customThe solid was triturated with ether
10. filtrationwas then collected by suction filtration

ORD record

ord-8eed8d6816654f348267ec1358ea8c36

Source dataset

uspto-grants-2011_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08026261B2